Stu says the PL30904 is a perfect fit. He has way more experience than I with the GV250.
That being said, here's what I've found: I bought the PL30904 about a year ago, just now getting serious about changing it.
When removing the CVT cover I see a Bando belt with the Kymco name and number (23100-KHE7-9000.)
With my sad, old eyes, I could see that the Gates was narrower. Will that cause a reduction in top speed?
By the book, the Gates is 893x23x28. Bando is 893x24x30.
Very slight difference, I know, but, I'm a Virgo. We're like that.
I did not install the Gates. First, because I want what appears to be factory original, (the Bando,) and, because I couldn't get the 19mm nut loose.
I haven't been on the Forum for a while, but, I hope you post an update, to let us know how the Gates works out for you.
I'll also mention that I've put 3000 miles on my GV since I've had it, and I see no sign of belt wear, and very little belt dust inside the cover. I still want to change it, only because the scoot is 12 years old, and I don't know how old the belt is.